Stable,highly concentrated dye solution of anthraquinone dyes in water miscible solvents

ABSTRACT

STABLE CONCENTRATED SOLUTIONS OF ANTHRAQUINONE DYES IN SOLVENTS WHICH ARE MISCIBLE WITH WATER AND WHICH ARE USEFUL FOR THE PREPARATION OF DYE LIQUORS FOR DYEING NATURAL OR SYNTHETIC POLYAMIDES. FOR DYEING OR PRINTING NITROGEN FIBROUS MATERIAL, FOR EXAMPLE WOOL, SILK OR SYNTHETIC POLYAMIDE FIBERS, IT IS PRINCIPALLY ANIONIC DYES WHICH ARE USED. THESE DYES ARE USUALLY SUPPLIED IN THE FORM OF FINELY GROUND POWDERS, CONTAINING STANDARDIZING AGENTS, WHICH HAVE TO BE DISSOLVED OR DISPERSED IN THE DYE LIQUOR FOR DYEING. APART FROM THE UNPLEANSANT DUST DEVELOPMENT OF THE INTENSELY COLORING DYES CAUDES BY THE POWDER FORM AND THE RISK OF AGGLOMERATION OF THE DYE POWDER, IT IS BY NO MEANS EASY TO DISSOLVE OR DISPERSE THE SOLID DYE IN THE DYE LIQUOR BECAUSE THE DYE USUALLY HAS INADEQUATE SOLUBILITY IN WATER.

United States Patent Ofice 3,671,176 Patented June 20, 1972 STABLE, HIGHLY CONCENTRATED DYE'SOLU- TION OF ANTHRAQUINONE DYES IN WATER MISCIBLE SOLVENTS Otto Kaufmann, Ludwigshafen, Manfred Daeuble, Frankenthal, Heinz Guenter Witsch and Enno Luebcke, Ludwigshafen, and Dimiter Bayew, Mannheim, Germany, assignors to Badische Anilin- & Soda-Fabrik Aktiengesellschaft, Ludwigshafen (Rhine), Germany No Drawing. Filed Sept. 8, 1969, Ser. No. 856,185 Claims priority, application Germany, Sept. 12, 1968,

P 17 94 132.1 Int. Cl. C09b 1/34 US. Cl. 8-39 4 Claims ABSTRACT OF THE DISCLOSURE Stable concentrated solutions of anthraquinone dyes in solvents which are miscible with water and which are useful for the preparation of dye liquors for dyeing natural or synthetic polyamides.

For dyeing or printing nitrogenous fibrous material, for example wool, silk or snythetic polyamide fibers, it is principally anionic dyes which are used. These dyes are usually supplied in the form of finely ground powders, containing standardizing agents, which have to be dissolved or dispersed in the dye liquor for dyeing. Apart from the unpleasant dust development of the intensely coloring dyes caused by the powder form and the risk of agglomeration of the dye powder, it is by no means easy to dissolve or disperse the solid dye in the dye liquor because the dye usually has inadequate.

solubility in water.

Light to medium shades are dyed from long liquors and therefore dissolving difiiculties do not usually arise, especially as the boiling temperature or a temperature above 100 C. is normally used. When full shades are dyed, however, it is often impossible even at the boil-- ing temperature to completely dissolve the dye used. The dye may then be deposited in undissolved form on the material being dyed and may provide poor fastness to rubbing. Particular difiiculties are caused when the liquor flows through the tetxile material during dyeing for example in the dyeing of cheeses or cloth on a beam dyeing machine. It is possible that undissolved dye particles are thus be filtered off and precipitated on the textile material, the consequence of which is particularly poor fast ness to rubbing.

Particularly great diificulties occur when fairly high dye concentrations have to be used for continuous dyeing processes and in textile printing. If it is not possible to disperse the undissolved dye constituents of a padding liquor or print paste adequately finely, nonuniform and speckled dyeings or prints are obtained.

A good fine dispersion of the sparingly soluble dye powder used can be achieved by first grinding it together with a dispersing agent, for example a reaction product of formaldehyde with naphthalenesulfonic acid or phenolsulfonic acid, into an aqueous paste and then drying it to give a fine, substantially homogeneous powder. However, the fineness of powders produced in this way is limited and it is extremely difficult, especially in the case of dyes which have only slight solubility in water, to achieve a predetermined degree of fineness which is necessary particularly for continuous dyeing methods, because recrystallization may occur even during the grinding of the paste made up of water, dye and dispersing agent and this runs counter to the dispersion desired.

These finely dispersed powders also contain quite considerable amounts of dispersing agent which, especially in continuous dyeing methods, may cause disturbances when full shades are to be obtained on a material which can only take up a very limited amount of the padding liquor. This is the case for example with closely woven polyamide filament fiber material.

It is often not possible to obtain a stable padding liquor at all with the necessary large amounts of dye because strong agglomeration effects may occur at high concencentrations which result in uneven and very speckled prints and dyeings. The large amount of dispersing agent introduced with the dye also disturbs the fixing of the dye on the fiber, especially by the steam and thermosol methods.

Attempts have also made to obviate the difficulties involved in dissolving large amounts of dye powder by using a fiowable dye preparation instead of powder.

In order to produce such preparations, the dye, dispersing agent and water have to be ground most carefully to a paste until the desired degree of fineness has been achieved and a mobile pourable paste is obtained. Only dyes which are very sparingly soluble in water may, however, be used.

The dye dispersions thus obtainable are easier to handle in the preparation of padding liquors and print pastes, but they have a number of serious disadvantages. It 1s, for instance, not possible to increase the dye contentof the pastes beyond 15 to 20% if they are to remam fluid, because a thickening of the suspensions and also thixotropic effects occur at higher concentrations and these make the handling of the preparation extremely troublesome. Settlement of the particles of dye to the bottom of the vessel is particularly troublesome; this occurs especially upon prolonged storage and may result in a solid sediment which can no longer be homogeneously distributed by shaking the vessel or stirring. There is a risk of a sediment forming particularly when high temperatures due to any external influence, occur during storage of the liquid dispersions. Aqueous suspensions are moreover susceptible to cold because the water may freeze and then it is necessary to thaw with particular care so that no agglomeration takes place and the fine dispersion is not disturbed.

The difiiculties which occur in dyeing granules or powders of synthetic polyamide with powdered dyes or disperse dyes are particularly serious if these granules are to be used as starting material for the production of filaments or shaped articles from the melt. Reference may be made here in particular to the production of filaments and injection moldings by melt spinning.

Apart from the fact that the dyes used in spin dyeing and in injection molding methods have to meet high demands as regards temperature stability and their behavior in the filaments and shaped articles, it is essential for the properties of the finished filaments and moldings and for their behavior during spinning and molding that, in particular, the dye be homogeneously dispersed and that there be no insoluble dye constituents or other solid impurities present. Since as a rule the dye incorporated into the polyamides disturbs the normal structure, these disturbances may be disregarded only if they do not have a detrimental effect on the natural properties, particularly the mechanical properties, of the products prepared from the polyamides. Disturbances occur, however, when fairly large dye particles or impurities results in irregularities in the structure of the polyamides. Such irregularities caused by large dye particles or by impurities can E) NH:

where R denotes an unsubstituted or substituted alkylene, cycloalkylene or arylene radical and X denotes a hydrogen atom or a radical having the formula:

SOKH

and an oxygen-containing solvent which is miscible in all proportions with water, are eminently suitable for dyeing textile material of nitrogenous fibers or for dyeing granules of synthetic polyamides and do not exhibit the said disadvantages of powder dyes.

Examples of nitrogenous fibers are those of natural of synthetic polyamides such as Wool, silk or nylon 6, nylon 6, 6 or compounds having an analogous chemical constitution.

The dye solutions contain the dye preferably in a concentration of to 40%, particularly to 30%.

These solutions are obtained when dyes having the said formula (which may also be present in the form of their alkali metal salts), preferably in dry form, are dissolved in the oxygen-containing solvent which is miscible in all proportions with water, if necessary at elevated temperature, for example at elevated temperature, for example at 30 to 100 C.

Examples of radicals R-X in the anthraquinone dyes are as follows:

(custom, (0110110113, @O Q SOBH C? *G l 3 NH:

SOzNE and The dyes may be prepared by reaction of 1-amino-4- haloanthraquinone-2-sulfonic acids with monoamines or diamines by conventional methods. Such methods of preparation are known for example from German patent speci- :fications No. 280,646; 534,931; 572,817 or 644,408 and from French patent specification No. 1,482,615.

Of special industrial importance are solutions according to this invention which contain, as dyes, the com pounds having the formula:

where Y denotes a radical having the formula:

S O gNHz I ll When dissolving the dyes it may be advantageous to add an amount of a compound having an alkaline reaction such as caustic soda solution, caustic potash solution, monoethanolamine or another aliphatic amine such that a solution prepared from the stock solution by dilution with water has a pH of from 3 to 7. Furthermore, it has been found that it is often very advantageous to pretreat the dye with a dilute mineral acid, particularly hydrochloric acid, before dissolving it in the oxygen-containing solvent. The properties of stock solutions prepared from dyes pretreated in this way are thus improved with regard to storage stability and solubility.

The dye solutions according to this invention, which may also be referred to as stock solutions, are miscible in all proportions with water without precipitating the dye, irrespective of whether they are diluted with water or poured into water.

=Aqueous solutions which have been obtained by diluting the stock solution with water and which contain about 10 to 20 g. of dye per liter, may even be boiled for an hour while stirring Without the dye being precipitated in any appreciable amount. The stock solutions have a low viscosity and are stable even at temperatures far below freezing point. Similarly, an increase in temperature to, for example, 40 to 60 C. has no detrimental effect, rather the stability of the solutions is improved thereby; an increase in temperature thus has the opposite effect to that in the case of suspensions containing the dispersing agents previously described.

Solvents which are miscible in all proportions with water and which are suitable for the production of stock solution are for example alcohols, particularly polyhydric alcohols having vicinal hydroxyl groups and their esters and ethers; ethanolamines and open-chain or cyclic carboxamides or mixtures of such compounds. The alcohols and their esters and ethers may hear one or more carboxylic or ketone groups as substituents. The following specific compounds are given as examples: ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, ethylene glycol mono-b-butyl ether, ethylene glycol monomethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, triethylene glycol mono-n-butyl ether, glycol monoacetate, glycerol, glycol aldehyde, glycolic acid, ethylene carbonate, propylene carbonate, butyrolacetone, pyrrolidone-Z, N-methylpyrrolidone dimethylformarnide, tetrahydrofurane, dioxane and dimethyl sulfoxide.

Of the said solvents it is preferred to use glycols having two to eight carbon atoms such as diethylene glycol or triethylene glycol, or glycol ethers having three to 12 carbon atoms such as diethylene glycol mono-n-butyl ether or triethylene glycol mono-n-butyl ether, or dimethylformamide or mixtures of these solvents.

Adducts of ethylene oxide to alcohols having more than six carbon atoms or to alkylphenols may advantageously be used as additives, but more ethylene oxide molecules (corresponding to the large number of carbon atoms) have to be added on so that the compounds are soluble in water. In the case of nonylphenol, for instance, at least six to seven moles of ethylene oxide is necessary, in the case of coconut oil about eight moles of ethylene oxide is necessary. When using adducts having a high number of carbon atoms it is advantageous to add them together with salts of alkylbenzenesulfonic acids with organic amines, particularly with monoethanolamine, diethanolamine or triethanolamine, so that thorough dissolution or mixing is achieved when they are poured into water. Hemiesters of glycols, diglycols, triglycols or tetraglycols or monoesters of glycerol, tetritols, pentitols or hexitols with aliphatic carboxylic acids having two to five carbon atoms are suitable as additives.

When dyeing textile material or granules, the liquor may be allowed to circulate at first in the usual way with auxiliaries and the acid or buffer salts necessary to set up the required pH; the dye is then added in the form of the stock solution. Organic acids and bases, for example acetic acid or triethanolamine, have proved to be most suitable for setting up the pH required.

Auxiliaries include those conventionally used in dyeing, for example adducts of ethylene oxide to aliphatic alcohols or alkylphenols and their hemiesters with sulfuric acid, adducts of ethylene oxide to aliphatic amines, sulfonation products of castor oil, of oleic acid and amides thereof with aliphatic amines, alkylbenzenesulfonic acids or alkylnaphthalenesulfonic acid. Mixtures of the said auxiliaries, especially those which have no cloud point at boiling temperature, are particularly advantageous. These auxiliaries, and mixtures thereof, are known and have often been described in the literature.

The dye is absorbed very Well by the fibers or granules during dyeing and there is an excellent exhaustion of the dye liquor which is very important in the case of full shades. Since no deposits or precipitates occur during dyeing, the dyeings have very good fastness to rubbing. This is very important especially in package dyeing where the dye liquor flows through the material.

In continuous dyeing, the use of stock solutions facilitates to a great extent the preparations of the padding liquors. The time-consuming dissolving or dispersing of large amounts of dye powder is no longer necessary because the stock solutions only have to be poured or stirred into the aqueous solution to which any necessary auxiliaries and thickeners have already been added. This is especially advantageous when large yardages of floorcoverings of polyamide fibrous material such as tufted carpets or needleloom material have to be dyed continuously and therefore several cubic meters of padding liquor is necessary per batch.

The fact that the dye goes on much better in solutions prepared in this way offers further advantages. With unchanged steaming periods, the dyes are not only fixed better on the synthetic polyamide fibers or wool, but also on the hard fibers which form the backing of tufted carpets and needleloom material. This is particularly important when dyeing full shades. In addition to the better fixing of the dye thus achieved, another advantage of the dyes according to the invention is the marked improvement in fastness to rubbing of the dyeings as compared with dyeings with powder dyes, and this is of particular importance in the case of fioorcoverings.

When dyeing polyamide granules or powders, the stock solutions may be used direct without preparing a dye bath for dyeing. The polyamide material is uniformly covered with the dye solution in the form of a film; the solvent is then removed. It is advantageous to filter the stock solution before use; in this simple way it is possible to free the solution from solids which not only cause the difficulties already mentioned but may also result for ex-- ample in production disturbances caused by clogging of the spinnerets.

The invention is illustrated by the following examples. Statements as to parts and percentages in the following examples relate to weight.

EXAMPLE 1 100 parts of the dry dye (prepared from 2 moles of 1- amino-4-bromoanthraquinone-Z-sulfonic acid and 1 mole of di-(p-aminophenyl)-methane by the process of German patent specification No. 644,408) is introduced at C. into a solvent mixture of 160 parts of dimethyltformamide and 160 parts of ethylene glycol bis-18-hydroxyethyl ether (=triethylene glycol) and stirred at this temperature for 30 minutes. The mixture is then cooled to 20 C. and the remaining residue is suction filtered. The solution obtained is stable to crystallization and may be diluted with Water in all proportions.

A print paste is prepared from 30 parts of this solution, ten parts of the triethanolamine salt of dodecylbenzenesulfonic acid, eight parts of the adduct of two moles of propylene oxide and five moles of ethylene oxide to lsononalnol, seven parts of p-chlorophenyl monoglycol ether and 30 parts of 60% acetic acid, and Wool tops are printed therewith in a mlange printing machine. The dye is then fixed by steaming for one hour at C. in a saturated steam atmosphere. The print is then rinsed, dried and stretched. A greenish blue dyeing having good Wet fastness is obtained. Tops of synthetic polyamide fibers may also be printed by the same method, and again a mlange-colored fabric is obtained having good wet, rubbing and light fastness properties.

EXAMPLE 2 100 parts of the dry dye of Example 1 (or X parts of water-moist suction filter cake equivalent to 100 parts of drydye) is boiled in 3,000 parts of 2% hydrochloric acid for 30 minutes, suction filtered, washed with 0.5% hydrochloric acid and dried. The mother liquor and Washing liquor contain practically no dye. The dry dye obtained is introduced at 80 C. into a solvent mixture of parts of triethylene glycol and 160 parts of dimethylformamide. The dye goes into solution easily. When filtered there is practically no residue left on the filter. 4 parts of 50% caustic soda solution is added to the filtrate. The solution obtained is mobile and may be diluted to an unlimited extent with water without precipitation taking place.

2 parts of this dye solution is placed in a tops dyeing apparatus which contains 1,000 parts of water at 50 0., 100 parts of nylon-6 tops, 1 part of the sodium salt of the terminally sulfonated adduct of 80 moles of ethylene oxide to sperm oil alcohol and 0.5 part of the adduct of 10 moles of ethylene oxide to stearylamine. The whole is heated within half an hour to the boiling temperature and dyeing is carried out for one hour at this temperature.

A greenish blue dyeing having excellent rubbing and washing fastness is thus obtained.

EXAMPLE 3 '100 parts of the dry dye prepared from 1 mole of lamino-4-bromoanthraquinone-2-sulfonic acid and 1 mole of p-toluidine according to the process of German patent specification No. 280,646 (or X parts of the water-moist suction filter cake equivalent to 100 parts of dry dye) is boiled in 5,000 parts of 3% hydrochloric acid for 30 minutes, then suction filtered, washed with water and dried. The dry dye obtained is introduced at 80 C. into a solvent mixture of 100 parts of triethylene glycol, 100 parts of diethylene glycol mono-n-butyl ether (butyl diglycol) and 100 parts of dimethylformamide, stirred for 20 minutes at this temperature and then nine parts of 50% caustic soda solution is added. The whole is cooled to 20 C. and the solution is filtered, practically no residue being left on the filter. The solution is mobile, stable and can be diluted in all proportions with water.

A solution having similar properties is obtained when 100 parts of a dye is used which has the formula:

Two parts of the dye solutions obtained according to the first paragraph of this example is added to 3,000 parts of water, ten parts of sodium sulfate and two parts of acetic acid which are in a winch dyeing machine. 100 parts of woollen fabric is dyed with this solution for 30 minutes at the boil and then two parts of formic acid is slowly added and dyeing is continued for another 30 minutes in the boiling liquor.

A blue woollen fabric is obtained; the dyeing has excellent fastness to rubbing.

EXAMPLE 4 100 parts of the dry dye (prepared from 1-amino-4- bromoanthraquinone-Z-sulfonic acid and the dihydrotricyclopentadienylamine having the formula:

according to the process of French patent specification No. 1,482,615; Example 1) is introduced at 80 C. into a solvent mixture of 100 parts of triethylene glycol, 100 parts of diethylene glycol mono-n-butyl ether (butyl diglycol) and 100 parts of dimethylformamide; 8.5 parts of tri-(B-hydroxypropyl)-amine (triisopropanolamine) is then added and the whole stirred for 20 minutes at 80 C. A mobile solution is thus obtained which can be diluted in all proportions with water without precipitates being formed. The solution is eminently suitable for dyeing polyamide blue shades.

A solution having similar properties is obtained by dissolving 100 parts of the dry dye having the formula:

II I

100 parts of a knitted material of polyamide-6 is dyed with 3 parts of dye solution and the additives enumerated in Example 2 in a beam dyeing machine. After boiling for minutes, a reddish blue material is obtained having very good fastness properties in general.

EXAMPLE 5 parts of the dry dye having the formula:

SOJH

OzNHz EXAMPLE 6 parts of the dye prepared according to Example 11 of German patent specification No. 1,028,717 is heated in 5,000 parts of a 4% hydrochloric acid for four hours at 110 C. to eliminate hexamethylenediarnine, cooled, suction filtered, washed with 0.5% hydrochloric acid and dried. The dye thus obtained is introduced into a solvent mixture of parts of triethylene glycol and 150 parts of dimethylformamide at 80 C. and 4 parts of 50% caustic soda solution is added. The dye solution thus obtained is eminently suitable for dyeing polyamide blue shades.

EXAMPLE 7 Granules of polyamide-6 are dyed in a stainless steel dyeing vessel provided with a stirrer, heating means and cooling means in an aqueous liquor at a liquor ratio of about 1:1 with 0.6% of the dye solution described in Example 6; dyeing is carried out for three hours at 98 to 99 C. and at atmospheric pressure, while stirring slowly. The dye material is then cooled to 30 to 40 C. The dye liquor is drained oil and the granules are washed three times with water, dried at 70 to 80 C. in a vacuurn of about 1 mm. Hg, spun in known manner in a grid melter and stretched to textile multifilament threads having a capillary titer of 5 denier. Blue filaments are obtained having satisfactory spinning and stretching properties and good fastness to light, washing (60 0.), dry cleaning, perspiration and rubbing.

EXAMPLE 8 Granules of polyamide-6 are dyed in a dyeing vessel as described in Example 7 in an aqueous liquor at a liquor ratio of 2.5 :1 with 1.2% of the dye solution described in Example 6 with an addition of 2 g./liter of ammonium acetate for three hours at 98 to 99 C. The dyed material is then cooled to 30 to 40 C., aftertreated as 9 described in Example 7, spun in an extruder spinning apparatus and stretched into textile threads having a capillary titer of denier. Filaments similar to those described in Example 7 are obtained having greater depth of color.

EXAMPLE 9 Polyamide-6 granules are dyed in a dyeing autoclave made of stainless steel and fitted with a heating and cooling jacket with 1.8% of the dye solution prepared according to Example 6 in an aqueous liquor at a liquor ratio of 1:1 and with an addition of 10 g. of 10% acetic acid per kilogram of granules for one hour at 130 C. (about 2 atmospheres gauge), while stirring slowly. The granules are then cooled, separated from the liquor, washed and dried. Finally the dyed granules are spun in an extruder spinning apparatus into filaments having a capillary titer of 20 denier and stretched. The spinning and stretching process is troublefree and spin-dyed threads having good fastness properties are obtained which are suitable for example for carpets.

EXAMPLE l0 Polyamide-6 granules which have been dried to a residual moisture content of less than 0.1% are drummed at room temperature in a vacuum tumble dryer with 0.8% of the dye solution according to the Example 6 which has been filtered before use, then freed from solvent by applying subatmospheric pressure and raising the temperature. The granules are then spun in an extruder spinning apparatus to multifilament threads having a capillary titer of 20 denier. By this method, too, spin-dyed threads having good fastness properties are obtained which are very sutiable for the textile field, for example in the manufacture of carpets.

We claim:

1. A stable, highly concentrated dye solution which is resistant to frost, capable of unlimited dilution with water and contains an oxygen-containing organic solvent capable of unlimited dilution with water, said solution comprising as the dye, in a concentration of to 40% by weight, at least one dye having the formula I HN-R-X wherein -R--X represents one of the radicals (OHz)aCH (CH2)11CH H SIOQH SO zNHz II I O NH-Y in which Y denotes a radical having the formula:

(la-C} CH.

SO NHg I'm. II

3. A solution as claimed in claim 1 which contains as the solvent triethylene glycol, diethylene glycol moon-nbutyl ether, triethylene glycol mono-n-butyl ether, dimethylformamide or mixture of these solvents.

4. A solution as claimed in claim 1 wherein said dye is present in said solution in a concentration of 20 to 30% by weight.

(References on following page) 12 References Cited OTHER REFERENCES UNITED STATES PATENTS Ciba, Belgian Patent No. 716,883 (Dec. 20, 1968) 1 735 147 11 1929 Weinand 2 0 371 [Abstract DeIWeIlt g- 51/68] 1,948,183 2/ 1934 Nawiasky et a1 260371 3,461,141 8/1969 Graser et a1. 260371 5 GEORGE E LESMES Pnmal'y Exammer 3,265,461 8/ 1966 Luetzel et a1. 8-84 P. C. IVES, Assistant Examiner FOREIGN PATENTS Us CL 1,178,356 1/1970 Great Britain 879 1,071,074 6/1967 Great Britain. 10 8*79;26 367 371 

